Pulverizer and classifier



Dec. 7, 1965 w. H. LYKKEN 3,221,998

PULVERIZER AND CLASSIFIER Filed April 29, 1963 3 Sheets-Sheet 1INVENTOR. W11. L 1AM h. A YKKEN AT TORNEYJ Dec. 7, 1965 Filed April 29,1963 W. H. LYKKEN PULVERIZER AND CLASSIFIER 3 Sheets-Sheet 2 INVENTOR.VWLLlflM/iLYK/(EN ATTORNEYJ Dec. 7, 1965 w. H. LYKKEN 3,221,998

PULVERIZER AND GLASSIFIER Filed April 29, 1963 3 Sheets-Sheet 5 FIG.4

INVENTOR. I/V/LuAM/iLrK/(EN Arron/vex;

United States Patent O 3,221,993 PULVERIZER AND CLASSTFIER William H.Lyklren, Springfield, Ohio, assignor to The Mierocyclomat Co.,Minneapolis, Minn., a corporation of Delaware Filed Apr. 29, 1%3, Ser.No. 276,457 6 Claims. (Cl. 241-56) This invention relates to anapparatus for the separation and extraction of solid materials, such asthe separation of asbestos fibers from asbestos bearing ores andextraction of gangue, and the like. Other exemplary uses of saidapparatus include the extraction of Contaminants from clay, talc, andsimilar non-metallic minerals for the purpose of upgrading them.

The invention is illustrated in the accompanying drawings in which thesame numerals refer to corresponding parts and in which:

FIGURE 1 is a side elevation of apparatus for carrying out a separationand extraction process;

FIGURE 2 is a top plan of the same apparatus;

FIGURE 3 is an end elevation of the same apparatus;

FIGURE 4 is an elevation in section and on an enlarged scale through theapparatus and on the line 4-4 of FIG- URE 2 and in the direction of thearrows;

FIGURE 5 is an end elevation of a modified form of apparatus; and,

FIGURE 6 is a partial plan view of the modified apparatus.

Referring to the drawings, the apparatus comprises a cylindrical casing10 housing means for reducing and dispersing the material to beseparated and extracted. Casing 19 is supported on a base 11 which alsosupports a motor 12 of sufiicient size and capacity to operate theapparatus. Conventional drive means, such as belts 13, connect the motorto the mechanism housed within casing 10. A feed hopper 14 is supportedon an arm 15 cantilevered out from the casing 10. Hopper 14 is connectedto the casing 10 by means of a tubular conduit 16 enclosing a helicalscrew feed 17. The screw feed 17 is driven by a separate electric motor18 through an appropriate drive enclosed within a safety housing 19.

Referring now to FIGURE 4, the apparatus includes a shaft 20 journaledin upper and lower bearings 21 and 22 for rotation about a vertical axiscentrally within casing 10. Bearing 22 is supported on the base 11. Oneend of shaft 20 extends through the bearing and base and is pro videdwith a multiple groove pulley 23 to adapt the shaft for rotation throughthe belt drive 13 from motor 12. Shaft 20 is provided with a keyway 24for attachment of rotor elements for rotation with the shaft.

The bottommost rotor element includes a hub 25 to which is attached anannular bottom plate 25 which carries a plurality of spaced radialblades 27 at its periphery. Plate 26 and radial blades 27 function as afan for drawing air through an annular opening 28 in the annular bottomplate 29 of casing 10 for the purpose of diluting and dispersing thematerial feed from hopper 14. Air inlet opening 28 is controlled by aplurality of slide dampers 30 for regulation of the volume of airadmitted.

Hub 25 supports a further annular plate 31 which carries a plurality ofspaced radial blades 32 at its periphery. Additional hubs 33 are mountedon the shaft 20. Each hub 33 supports an annular plate 31 carryingspaced radial blades 32. Each rotor stage represented by an annularplate 31 and series of radial blades 32 is separated from the adjacentstages by an annular disc 34 supported on the rotor shaft between thehubs.

As is well-known in the art, the several rotor stages act upon thematerial fed into the lower portion of the casing 10 to reduce anddeagglomerate the solid material "ice by air attrition and impactbetween the particles and rotor blades and housing wall. At the sametime, the solid material is thoroughly diluted and dispersed in the airstream drawn in through the bottom air inlet. The material is acted uponin intrablade vortices between adjacent radial blades 32 spaced aboutthe periphery of the rotor sections and in a rising vortex between theouter periphery of the rotor sections and the housing wall. The desiredparticles are physically separated from any bonded impurities orcontaminants. The desired particles are gen erally reduced in size. Theimpurities are generally more difficult to grind and thus are ground toa lesser extent.

The mixture of reduced and thoroughly dispersed solid material andseparated contaminants rises into the upper chamber 35 of the casing 10and into the cylindrical classifying or extracting casing 36 mounted ontop of the casing 10. A further hub 37 is positioned on shaft 20 forrotation therewith in cylindrical housing 36. Hub 37 is spaced from thereducing and dispersing rotor elements by means of a series of spacerrings or sleeves 38. Hub 37 supports a pair of annular plates 39 and 46held spaced apart by means of a spacer ring 41. A plurality offingerlike radiating blades or rods 42 are supported between plates 39and at their outer periphery for rotation within cylindrical housing 36.

A fan housing 43 is disposed on top of the apparatus above thecylindrical classification housing 36. An annular diaphragm ring 44 isdisposed between the classifier housing 36 and the fan housing 43. Anannular opening 45 defined by the inner periphery of diaphragm ring 44and the shaft hubs forms an opening communicating between the twohousings.

A fan hub 46 is secured to shaft 20 for rotation therewith within fanhousing 43. Hub 46 supports an annular plate 47 which in turn carries aplurality of spaced radial fan blades 48 at its outer periphery. Fanhousing 43 is in the form of an involute scroll as is conventional inthe art. The scroll housing terminates in a discharge port or conduit 49which leads to a collector for receiving the material discharged fromthe apparatus. The fan functions to induce a flow of air and materialthrough the apparatus and to discharge the lighter finer solid materials(which in most cases are the desired materials) separated from theoriginal feed.

In order to get from the top zone 35 of the material reducing anddispersing housing, the finer and lighter material must first pass intoclassifier housing 36, where it is freed from the coarser and densermaterials, and must pass between the finger-like blades or rods 42 andbe drawn centripetally through the narrow passage 50 between the innerlip of diaphragm ring 44 and the outer lip of plate 40. The materialwhich makes its Way through passage 50 is then caught up and entrainedin the stream of the fan blades and discharged out through conduit 49.

The coarser denser materials (which in most cases are the impurities orcontaminants) which are rejected by the classifier rotor, are throwncentrifugally outwardly to the cylindrical wall of housing 36 and arecaught by one of several coarse discharge or extraction conduits 51spaced about the wall of the classifier housing 36. One end of eachdischarge conduit 51 is in communication with a passage 52 in the wallof classifier housing 36. The opposite end of each discharge conduit 51is fitted with a flapper extraction valve 53.

Extraction valve 53 is composed of a resilient tube of rubber orsynthetic rubber-like resinous material. One end is attached to conduit51 by means of a clamp 54 or similar fastening device. The opposite endis flattened and is adapted to normally remain closed. However, becauseof the resilience of the material of which the flapper valve is formed,the sides of the valve which are normally in face-to-face abuttingposition are forced apart by the accumulation of coarse dense matrial inthe valve 53 and discharge conduit 51 so as to be discharged from theap: paratus. The extraction valve then closes automatically. In mostinstances the coarser denser material discharged through valve 53 is theunwanted material and is discarded after its discharge from the valve.

In FIGURES 5 and 6 there is shown an alternative form of apparatus inwhich the extractor or bleeder valve is replaced by a bleeder cyclone.The basic apparatus has substantially the same structure as that alreadydescribed except that a modified coarse discharge conduit 51A extendstangentially into the top cylindrical portion of a conventional uppercyclone 55. The lower conical portion of the upper cyclone 55 extendsinto the top wall of a lower cyclone 56. The bottom discharge end ofcyclone 56 is fitted with a gravity operated seal or valve 57. Valve 57includes a conduit having a diagonal opening against which is fitted aplate 58 hinged at 59 and having a threaded rod 60 extending out fromthe plate and fitted with an adjustable counterweight 61.

The extracted coarser and denser particles are separated from the air inthe cyclones. The solid material passes downwardly through the cyclonesand collects in the valve 57. When a sufiicient weight of extractedparticles collect in the valve to counterbalance the plate 58 and itscounterweight, the plate pivots on its hinge and opens the conduit todischarge the contents of the valve. The valve then closes automaticallydue to the weight of the plate and counterweight.

The separated air and any fines entrained therein is desirably recycledthrough the apparatus. A conduit 62 extending from the top wall of theupper cyclone 55 is provided for this purpose. The conduit extends downto the base between the bottom of the reducing and dispersing rotor andthe base for reintroduction into the housing 10.

The apparatus of the present invention does two jobs simultaneously. Itprovides precise particle reduction and impurity extraction. Thecombined apparatus is a pulverizer-classifier including a heavy dutyhigh capacity air attrition mill with an integral classifier. It hasfound use in upgrading quality in many non-metallic mineral processingoperations where precisely controlled pulverization and positiveextraction of impurities are required. The present aparatus provides forthe sub-sieve size processing of filler clays, technical ceramics, lime,gypsum, rare earth oxides, pigments, asbestos, and similar friablematerials. It provides accurate control of particle reduction to anydesired average size from 150 microns to less than 1 micron. It providesfor the extraction of such impurities as silica, mica, sand iron etc.,which are usually found in non-metallic minerals. The elfectiveextraction of impurities produced by this apparatus upgrades the productand reduces the cost of grinding.

The apparatus according to the present invention has been found to beespecially useful in increasing the rate of recovery of asbestos. In thepast, normal recovery of usable asbestos fiber from asbestos ore wasbetween 4% and 6%. The rest of the ore was discarded as tailings. Bymeans of the present invention tailings piles are being reworked withsubstantially greater recovery of usable asbestos fiber than resultedfrom processing of the virgin ore. In the case of new ore, it is crushedto about inch mesh or finer before feeding to the apparatus. Millrejects and tailings may usually be fed directly.

Short asbestos fiber is used as a filler in plastic castings, asbestoscement, roofing cement, roof tile and Macadam road surfacing materialfor strength and .improved wearability. Starting with raw rock or milltailings, recovery rates of acceptable short asbestos fibers have beenas high as 40% to 55% by weight of the feed material. Finished asbestosfiber produced by other extraction processes has been upgraded by meansof the present invention by opening the fiber bundles to release trappedrock and iron to extract and discharge the same. With such finishedfiber starting material, recovery rates have been as high as 88% to 97%.

Clay occurs in huge natural deposits, generally in very fine particlesizes in the range of 2 microns and finer. Clay normally containsrelatively small amounts (about 2% to 3 of impurities in the form ofmica flakes, silica and silicates, traces, of iron, etc. For many usesthe presence of these impurities may not be objectionable. However,where the end use requires a very white color, as in the preparation ofpaper coatings, fine china and the like, the presence of even 2% to 4%impurities downgrade the product. By passing such clay through theapparatus of the present invention and extracting only 3% to 4% of thetotal clay feed, enough of the impurities are removed to raise the colorof the remaining material 2 to 3 points on the General Electric ColorTester.

Using a 30 inch diameter mill of 100 horsepower, the capacity of themill is 4,000 pounds of clay-per hour. Because the impurities are merelyextracted, instead of being ground, this rate of production can bemaintained. If it were necessary to grind the 2% to 3% impuritiespresent, the production would have to be cut to 1,000 pounds per hour orless. The wear on the machine would be increased and the color of thefinished product would be lower because impurities would still bepresent although in smaller size.

Talc is upgraded in much the same manner as clay. It occurs naturally inlarge deposits and contains small amounts of oversize impurities. Gypsumhas similarly been upgraded by extracting dolomite. Substantialquantitles of gypsum have been recovered from mill rejects. Cocoacontains about 2% to 3% fiber which is hard to grind and adds nothingbut bulk and weight to the product. By removing this 2% to 3% of fiberby the extraction process according to the present invention, grindingproduction of cocoa can be doubled.

It is apparent that many modifications and variations of this inventionas hereinbefore set forth may be made without departing from the spiritand scope thereof. The specific embodiments described are given by wayof example only and the invention is limited only by the terms of theappended claims.

I claim:

1. Extraction apparatus for the removal of coarser and denser impuritiesand contaminants from non-metallic solid materials to upgrade thequality of the same, said apparatus comprising a first generallycylindrical vertical casing, a second generally cylindrical verticalcasing of greater diameter but lesser axial depth mounted on top of saidfirst casing, the top of said first casing being open and incommunication with said second casing, an involute scroll fan housingmounted on top of said second casing; a vertical axis shaft extendingcentrally through said casings and fan housing and journaled forrotation therein, means to drive said shaft; a plurality of stackedclosed end grinding rotor stages mounted on said shaft for rotationtherewith in said first casing, each of said grinding rotor stagesincluding an annular horizontally disposed disk and a plurality ofspaced vertically disposed radial blades uniformly distributed aroundthe periphery of the disk, the free ends of said blades being spacedclosely inwardly from the inner wall of said first casing, an annularhorizontally disposed disk between each pair of grinding rotor stages, amaterial inlet to said first casing adjacent the lowermost of saidgrinding rotor stages; an independent air inlet to the bottom of saidfirst casing and below said material inlet, means for regulating theamount of air admitted to said air inlet, auxiliary fan means mounted onsaid shaft between said air inlet and the lowermost of said grindingrotor stages; a classifier rotor mounted on said shaft for rotationtherewith in the upper portion of said second casing, said classifierrotor comprising an an nular horizontally disposed disk and a pluralityof spaced horizontally disposed radial finger-like blades u lifqrrnlydistributed and extending around the periphery of said disks, the freeends of said blades being spaced closely inwardly from the inner wallsof said second casing; a horizontally disposed diaphragm ring mountedbetween said second casing and said fan housing closely spaced from saidclassifier rotor blades, the inside diameter of said ring defining theouter periphery of an annular passage between said second casing andsaid fan housing and being less than the diameter of said classifierrotor disk; at least one extraction port in the wall of said secondcasing disposed below the level of said classifier rotor disk, a conduitin communication with said port; and a fan rotor mounted on said shaftfor rotation therewith in said fan housing.

2. Extract-ion apparatus according to claim 1 further characterized inthat an extraction valve is provided in communication with saidextraction port and conduit, said valve being operative in response tothe weight of accumulated extracted material therein.

3. Extraction apparatus according to claim 2 further characterized bythe provision of a plurality of extraction ports and valves uniformlyspaced about the periphery of said second casing.

4. Extraction apparatus according to claim 2 further characterized inthat said extraction valve is a flapper valve composed of resilientmaterial in the form of a tube secured at one end to the conduit incommunication with the extraction port and flattened at the other end soas to be normally closed.

5. Extraction apparatus according to claim 2 further characterized inthat said apparatus includes a cyclone separator having a tangentialinlet in communication with said extraction port and conduit and abottom outlet fitted with said extraction valve.

6. Extraction apparatus according to claim 5 further characterized inthat said extraction valve is a pivotally mounted plate extending oversaid cyclone separator outlet, said plate being provided with anoutwardly extending arm and an adjustable counterweight on said armadapted to maintain said pivoted plate in a normally closed positionover said outlet.

References Cited by the Examiner UNITED STATES PATENTS 2,267,729 12/1941 Grindle 2415 6 2,440,285 4/1948 Lykken et a1. 241--56 2,497,0882/1950 Lykken et a1 241-56 X 2,561,388 7/1951 Lykken et a1. 241-56 X2,962,231 11/ 1960 Weston 24124 2,963,230 12/1960 Lykken et a1. 241-503,058,671 10/ 1962 Billue 241-24 3,071,330 1/1963 Jackering 241-53 I.SPENCER OVERHOLSER, Primary Examiner.

WILLIAM W. DYER, JR., Examiner.

1. EXTRACTION APPARATUS FOR REMOVAL OF COARSER AND DENSER IMPURITIES ANDCONTAMINANTS FROM NON-METALLIC SOLID MATERIALS TO UPGRADE THE QUALITY OFTHE SAME, SAID APPARATUS COMPRISING A FIRST GENERALLY CYLINDRICALVERTICAL CASING, A SECOND GENERALLY CYLINDRICAL VERTICAL CASING OFGREATER DIAMETER BUT LESSER AXIAL DEPTH MOUNTED ON TOP OF SAID FIRSTCASING, THE TOP OF SAID FIRST CASING BEING OPEN AND IN COMMUNICATIONWITH SAID SECOND CASING, AN INVOLUTE SCROLL FAN HOUSING MOUNTED ON TOPOF SAID SECOND CASING; A VERTICAL AXIS SHAFT EXTENDING CENTRALLY THROUGHSAID CASINGS AND FAN HOUSING AND JOURNALED FOR ROTATION THEREIN, MEANSTO DRIVE SAID SHAFT; A PLURALITY OF STACKED CLOSED END GRINDING ROTORSTAGES MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH IN SAID FIRSTCASING, EACH OF SAID GRINDING ROTOR STAGES INCLUDING AN ANNULARHORIZONTALLY DISPOSED DISK AND A PLURALITY OF SPACED VERTICALLY DISPOSEDRADIAL BLADES UNIFORMLY DISTRIBUTED AROUND THE PERIPHERY OF THE DISK,THE FREE ENDS OF SAID BLADES BEING SPACED CLOSELY INWARDLY FROM THEINNER WALL OF SAID FIRST CASING, AN ANNULAR HORIZONTALLY DISPOSED DISKBETWEEN EACH PAIR OF GRINDING ROTOR STAGES, A MATERIAL INLET TO SAIDFIRST CASING ADJACENT THE LOWERMOST OF SAID GRINDING ROTOR STAGES; ANINDEPENDENT AIR INLET TO THE BOTTOM OF SAID FIRST CASTING AND BELOW SAIDMATERIAL INLET, MEANS FOR REGULATING THE AMOUNT OF AIR ADMITTED TO SAIDAIR INLET, AUXILIARY FAN MEANS MOUNTED ON SAID SHAFT BETWEEN SAID AIRINLET AND THE LOWERMOST OF SAID GRINDING ROTOR STAGES; A CLASSIFIERROTOR MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH IN THE UPPER PORTIONOF SAID SECOND CASING, SAID CLASSIFIER ROTOR COMPRISING AN ANNULARHORIZONTALLY DISPOSED RADIAL FINGER-LIKE BLADE UNIFORMLY HORIZONTALLYDISPOSED RADIAL FINGER-LIKE BLADE UNIFORMLY DISTRIBUTED AND EXTENDINGAROUND THE PERIPHERY OF SAID DISKS, THE FREE ENDS OF SAID BLADES BEINGSPACED CLOSELY INWARDLY FROM THE INNER WALLS OF SAID SECOND CASING; AHORIZONTALLY DISPOSED DIAPHRAGM RING MOUNTED BETWEEN SAID SECOND CASINGAND SAID FAN HOUSING CLOSELY SPACED FROM SAID CLASSIFIER ROTOR BLADES,THE INSIDE DIAMETER OF SAID RING DEFINING THE OUTER PERIPHERY OF ANANNULAR PASSAGE BETWEEN SAID SECOND CASING AND SAID FAN HOUSING ANDBEING LESS THAN THE DIAMETER OF SAID CLASSIFIER ROTOR DISK; AT LEAST ONEEXTRACTION PORT IN THE WALL OF SAID SECOND CASING DISPOSED BELOW THELEVEL OF SAID CLASSIFIER ROTOR DISK, A CONDUIT IN COMMUNICATION WITHSAID PORT; AND A FAN ROTOR MOUNTED ON SAID SHAFT FOR ROTATION THEREWITHIN SAID FAN HOUSING.